Submersible vehicles (e.g., Unmanned Underwater Vehicles (UUVs)) sometimes utilize fuel cells to generate electricity. One example of a fuel cell is a Solid Oxide Fuel Cell (SOFC). SOFCs operate by electrochemically converting fuel and oxygen into electricity and heat. Typical SOFCs operate between about 650-850 degrees Celsius, and the conversion process is exothermic. This generates a large amount of waste heat which can be problematic in a UUV. Typically, the waste heat is removed from the UUV using a cooling loop, which transfers the heat to the water that surrounds the UUV.
For temperature control of the SOFC itself, a cathode blower is utilized to both provide oxygen to the cathode of the SOFC and to provide cooling to the SOFC. When the temperature of the SOFC rises near the upper end of the operating range, the speed of the cathode blower is increased to provide additional cooling to the SOFC. However, the cathode blower may utilize a significant amount of parasitic electrical power from the SOFC for the cooling activity, which reduces the electrical power that is available for the UUV. For instance, a cathode blower may utilize as much as 20% of the total electrical power generated from the SOFC when operated at its maximum flow rate. This maximum flow rate is often much higher than the flow rate that is necessary for oxidizing the fuel at the SOFC.